I need to draw a regular polygon on n sides, n <13 for side L, L <11 in cm. with semicircles on its sides, completely black in such a way that I save it as a xxx.png image to print and cut out later. The important thing is that the dimensions on the screen in cm. are identical to the image to be cropped later. Could you help me. I have seen several examples in the forum, like this one, but I can't find a way to modify it. I attach a picture of the idea.(but totally black without squares or borders, on a white background)
L = 12;
Graphics[Line[{{L, 0}, {L/2, L Sqrt[3]/2}, {-L/2, L Sqrt[3]/2}, {-L,
0}, {-L/2, -L Sqrt[3]/2}, {L/2, -L Sqrt[3]/2}, {L, 0}}]]